It's seriously easy to root as it has an unlocked bootloader (secretly Samsung wanted it to be a big hit with developers, they even gave a free S2 to the Cyanogen Mod team and then employed the lead dev. from CM). Just flash a CF-Root kernel (available on XDA), and the phone's rooted with SU, CWM & I think ROM manager pre-installed.

True, it's more for taking a system image than taking a copy of user media. It does copy text messages, call log etc. though.

Just stick all your media on a memory card and then take the card out of the phone, that way it'll all definitely be safe. It's probably easier to do all that media copying on a PC as when you plug an S2 in the card and the internal memory show up as 2 separate removable drives, making copying stuff across really easy .